Corrosion Resistance Of Ti6Al4V Alloy Research Articles

Enhancement of Wear and Corrosion Resistance of Ti6Al4V Alloy through Hollow Cathode Discharge-Assisted Plasma Nitriding.

In order to improve the wear and corrosion resistance of Ti6Al4V alloy, a Ti-N compound layer was formed on the alloy by plasma nitriding at a relatively low temperature (750 °C) and within an economical processing duration (4 h), in a mixture of NH3 and N2 gases with varying ratios. The influence of the gas mixture on the microstructure, phase composition, and properties of the Ti-N layer was investigated. The results indicated that the thickness of the nitrided layer achieved in a mixed atmosphere with optimal proportions of NH3 and N2 (with a ratio of 1:2) was substantially greater than that obtained in an atmosphere of pure NH3. This suggests that appropriately increasing the proportion of N2 in the nitriding atmosphere is beneficial for the growth of the nitrided layer. The experiments demonstrated that the formation of the surface nitrided layer significantly enhances the corrosion and wear resistance of the titanium alloys.

Tailoring surface properties and corrosion resistance of laser shock peened Ti6Al4V alloy by low-temperature annealing

The present study examined the effects of laser shock peening (LSP) and low-temperature annealing after LSP (LSPA) on the corrosion resistance of the Ti6Al4V alloy. The high density of dislocations in the LSP samples contributes to the rapid formation of a TiO₂ passive film during the electrochemical corrosion process. In this study, low temperature annealing was employed to further improve the corrosion resistance. The results indicated that the corrosion resistance of the LSPA samples was significantly improved compared to that of the LSP-treated samples. The LSPA treatment facilitated the pre-generation of a dense TiO2 passive film on the alloy surface via oxidation, reduced corrosion rate, inhibited the penetration of dissolved oxygen and ions present in the sodium chloride solution into the alloy surface. Meanwhile, low-temperature annealing could rearrange and annihilate dislocations, creating subgrains and relaxing non-equilibrium grain boundaries induced by deformation. This process reduced active sites and grain boundary energy, ultimately improving the corrosion resistance of the Ti6Al4V alloy.

Synergistic Enhancement of Strength, Ductility, and Corrosion Resistance of Ti6Al4V Alloy Through Low Cu Doping and Hot Extrusion

A Cu-containing Ti6Al4V alloy is considered an ideal biomedical material due to its excellent antibacterial properties. However, the addition of Cu leads to a mismatch in strength, ductility, and corrosion resistance, which hinders their further application. To address this issue, the study utilized low Cu doping and hot extrusion to optimize the material’s properties. The results showed that the primary lamellar structures were transformed into equiaxed grains, with an average grain size reduced from 10 μm to 300 nm. The nanoequiaxed grains had a homogeneous elemental composition and a stronger base texture, with orientations aligned with the extrusion direction. As a result, synergistic strengthening in terms of strength, ductility, and corrosion resistance was achieved. The film resistance increased from 127 kΩ·cm2 to 325 kΩ·cm2, the ultimate tensile strength (UTS) increased from 1,030 MPa to 1,330 MPa, and the elongation increased from 7% to 21%. These improvements were attributed to the nanostructure and basal texture, which facilitated the formation of a thicker passive film and reduced pitting corrosion, thereby enhancing corrosion resistance. Additionally, the nanoequiaxed grains could provide grain boundary strengthening and texture strengthening on UTS and ensure uniform deformation for elongation.

Comparison of surface modification and corrosion resistance of Ti6Al4V alloy using matcha tea extract-based silver and copper oxide nanoparticles

In this study, our aim was to investigate the application of green-synthesized silver nanoparticles (Ag NPs) and copper oxide nanoparticles (CuO NPs) for surface modification, specifically focusing on their influence on the corrosion properties of Ti6Al4V alloy. The green NPs were thoroughly characterized, and their role in enhancing the anticorrosive performance of Ti6Al4V was carefully evaluated. Various coating methods and drying temperatures were utilized to coat Ti6Al4V samples with the NPs, aiming to assess their impact on corrosion resistance. The electrochemical corrosion behavior was examined through electrochemical polarization tests in Ringer's bio-liquid. The study underscored the significant impact of coating type, coating method, and drying temperature (25 °C and 60 °C) in achieving favorable anticorrosive performance. Notably, samples oven-dried at both temperatures and coated with Ag NPs and CuO NPs using spray coating demonstrated the most effective substrate protection, achieving protection efficiencies of 97.37 % and 90.56 %, respectively. This outcome can be attributed to the unique spherical and homogeneously dispersed particulate structure of the NPs, effectively reducing microporosity. In summary, the combination of increased surface area and reduced microporosity resulting from the surface properties of the NPs underscores the potential of well-designed surface modification approaches in advancing the development of titanium-based implants for biomedical applications.

Investigation The Effect of Tellurium Addition on Corrosion Resistance of Ti6Al4V alloy

The purpose of this study is to investigate the impact of Tellurium alloying element (0,5, 1, 1,5, 2, 2,5, 3, 3,5, 4, 4,5 and 5 wt%) on corrosion resistance of Ti6Al4V alloy in Hank and saliva solutions. All alloys have been prepared by powder metallurgy technique, the compact pressure was determined as 800MP and the green samples sintered at 350 C0 for 1h then at 550 C0 for 1h and at 1000 C0 for 2 h in inert gas (of Argon), then the samples cooled in the furnace to room temperature. The microstructure was observed using a light optical microscope and has shown that all specimens of alloys contain two regions: the α-Ti phase and the β-Ti phase. Generally, compared with the base alloy, the addition of the Te element leads to an increase in the α-phase due to the effect of Te as the α stabilizer element. Electrochemical tests (potentiodynamic polarization and OCP – Time measurement) in Hank's and saliva solutions were used to evaluate corrosion resistance of Ti6Al4V alloy. When tellurium was added, the OCP shifted to the positive direction. This makes the alloy more noble and increases its resistance to corrosion by decreasing corrosion current density. The percentage of improvement ranges from 2,50 % to 61,92 % in saliva solution and from 16,27 % to 88,32 % in Hank's solution. For both solutions, the best percentage of improvement is 5 % Te

Effect of Repeated Processing Passes during Ultrasonic Rolling on Fatigue Performance and Corrosion Resistance of Ti6Al4V Alloy

Ultrasonic surface rolling processing (USRP) is a new method to improve the fatigue performance of titanium alloy, and repeated processing pass is an important factor that affects its strengthening effect. The effect of USRP passes on the surface microstructure, residual stress, fatigue performance and corrosion resistance of titanium alloy is researched via SEM, X-ray diffractometer, rotating–bending fatigue test and electrochemical impedance spectroscopy. The results show that Ti6Al4V alloy undergoes cumulative plastic deformation during USRP process, the surface grains are refined and a residual compressive stress field with a thickness of 500 μm is introduced, which together improve the fatigue performance of the Ti6Al4V alloy. Increasing the repeated processing passes will deepen the grain refinement layer and increase the surface hardening effect, but the fatigue life of the Ti6Al4V alloy does not increase with an increase in processing passes. A five-passes processing under a static force of 550 N can result in a greater gain for the fatigue resistance of the Ti6Al4V alloy; the fatigue life of a five-passes-processed sample under 600 MPa is 8 times higher than that of an untreated sample, and its fatigue crack source initiates at the subsurface away from the surface of 180 μm. Furthermore, Ti6Al4V alloys treated by USRP show a better corrosion resistance in both neutral and acidic solutions, especially for the five-passes-processed sample.

Enhancement of the electrochemical corrosion resistance of Ti6Al4V alloy reinforced by nano- and micro-TiC particles through directed energy deposition

Nano- and micro-size TiC ceramic particles were synergistically utilized for the reinforcement of Ti6Al4V alloy, manufactured through directed energy deposition. The corrosion current density of nano/micro-TiC/Ti6Al4V composite decreased by 23.7% and 74.6% compared to Ti6Al4V composites containing only TiC microparticles or only TiC nanoparticles, and by 77.8% compared to pure Ti6Al4V. A stable passive film of TiO2 with higher content of bound water is formed in nano/micro-TiC/Ti6Al4V composite specimen. The excellent electrochemical corrosion resistance of the nano/micro-TiC/Ti6Al4V composite is attributed to the α martensite transformation and the accumulation of [TiCl6]2- complexes, which promotes the formation of TiO2 passive film.

Effect of LaB6 doping on the microstructure, microhardness and corrosion behavior of laser cladded FeCoNiCrMo coating on Ti6Al4V

In order to improve the microhardness and corrosion resistance of Ti6Al4V alloy, LaB6 powders was added to the FeCoNiCrMo high entropy alloy coatings fabricated by laser cladding on Ti6Al4V. The microstructure, corrosion resistance and microhardness of LaB6/HEA coatings were analyzed by SEM, EDS, XRD, TEM and performance characterization equipment. The results showed that the appropriate content of LaB6 (2 wt%) could significantly reduce the cracking sensitivity of the coating, and in-situ synthesized La2O3 refined the microstructure and achieve fine grain strengthening. The reduction of cracks and refinement of the microstructure improved the corrosion resistance of HEA. At the LaB6 content of 2 wt%, the corrosion current density of the coating was 2.164 × 10−6 A·cm−2, passive potential was 1.339 V, and the number and size of pitting on the surface of the sample were the lowest, indicating that the passivation film had the strongest resistance to corrosive media. In addition, at the amount of LaB6 addition of 2 wt%, the microhardness of the coating could reach up to 987 HV0.3, which could be attributed to the in-situ synthesis of the ceramic phase TiBX and the refinement of the grains.

Laser shock wave-induced enhanced thermal corrosion resistance of Ti6Al4V alloy fabricated by laser powder bed fusion

In this study, the effect of laser shock peening (LSP) on the microstructural evolution and thermal corrosion behaviors of laser powder bed fusion processed (LPBFed) Ti6Al4V samples was characterised in Na2SO4 + NaCl mixed solutions at 500 °C, 600 °C and 700 °C. Thermal corrosion resistance was evaluated using thermo-kinetic curves, thermal corrosion products, and corrosion morphology. The results indicated that the thermal corrosion layer of the LSPed samples was thinner and denser than that of the LPBFed samples, and the mass gain of the LSPed samples was significantly reduced, suggesting a better thermal corrosion resistance. This is attributed to the refined grains, high-density dislocations, and nano-twins. Finally, the improvement mechanism of LSP on the thermal corrosion resistance of the LPBF-treated Ti6Al4V titanium alloy was revealed.

Characteristics of boronized Ti6Al4V alloy using boric acid based boronizing mixture

Boronizing processes of Ti alloys are generally performed in atmosphere-controlled furnaces. In this study, it is aimed to carry out boronizing process under atmospheric conditions by using an alternative boronizing mixture containing boric acid and to better the surface characteristics of Ti6Al4V alloy by boronizing. The efficiency of the boronizing mixture was evaluated by performing boronizing at different process temperatures (900-1100 °C) and durations (12 and 20 h). Microstructural (OM, SEM) and chemical (XRD, EDS, XPS) analyzes were performed to characterize the boride layers formed on the surfaces of the boronized samples. As a consequence of these analyzes, it was found out that a two-phase boride layer (TiB2 + TiB) was obtained in the samples. In addition, in vitro tests were done for specifying the bioactivity of boronized samples. In order to determine the effect of boronizing on the corrosion resistance of Ti6Al4V alloy, corrosion tests were performed by the Tafel extrapolation method. The adhesion behavior of the boride layers was determined by the Daimler-Benz Rockwell C indentation test. As a result, boronizing studies have been performed successfully without atmospheric-controlled conditions and it has been defined that surface characteristics of the Ti6Al4V alloy have bettered through the boride layers formed on the alloy surface.

Understanding the protective role of a gradient titanium oxide ceramic layer on Ti6Al4V against corrosion via analyses of Mott-Schottky curve and electron work function (EWF)

Thermal oxidation (TO) process was employed to generate a gradient titanium oxide ceramic layer for improving corrosion performance and service safety of Ti6Al4V alloy. The semiconductor characteristic of the TO layer was evaluated in CO2-saturated simulated oilfield brine. The generated TO layer with a thickness of about 20 μm was dense and continuous without cracks or spalling characteristics. The TO layer mainly comprised of an oxide ceramic layer (rutile TiO2 ceramic phase, minor anatase one, and Al2O3) and an oxygen diffusion layer. The conducted electrochemical analysis suggested that the corrosion resistance of Ti6Al4V alloy was improved using TO surface strengthening process. It was demonstrated that the TO layer with semiconductor characteristics showed a transition from n-type (donor) to p-type (acceptor) with the increasing applied electric potential. The electron work function of the TO layer was higher than that of Ti6Al4V alloy with a naturally formed passive film. The improvement in corrosion properties was attributed to the excellent chemical stability and semiconductor properties of the metal oxide ceramic phases (TiO2, Al2O3) in the TO layer.

Cathodic nitriding and anodic polishing of Ti6Al4V alloy by plasma electrolysis

The paper presents the results of studies on modifying the surface of Ti6Al4V titanium alloy by combined exposure to cathodic nitriding and anodic polishing in electrolysis plasma. The morphology and roughness of the surface, microhardness of the modified layer have been investigated. Wear resistance was studied under dry friction conditions. The effect of combined treatment on corrosion resistance of Ti6Al4V alloy was examined by means of potentiodynamic polarization in Ringer’s solution. It has been established that cathodic nitriding at 750 °C for 10 min leads to the hardening of the surface layer up to 820 HV with an increase in roughness by 2 times and wear resistance almost 3 times. Subsequent anodic plasma electrolytic polishing of the nitriding surface in solution of ammonium sulfate leads to a decrease in roughness and friction coefficient with an increase in corrosion resistance.

Hydroxyapatite and β-TCP modified PMMA-TiO2 and PMMA-ZrO2 coatings for bioactive corrosion protection of Ti6Al4V implants.

Organic-inorganic hybrid coatings deposited on different types of metallic alloys have shown outstanding anticorrosive performance. The incorporation of osteoconductive additives such as hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) into organic-inorganic hybrid coatings is promising to improve the osseointegration and corrosion resistance of Ti6Al4V alloys, which are the most widely used metallic orthopedic and dental implant materials today. Therefore, this study evaluated the capability of poly(methyl methacrylate) (PMMA)-TiO2 and PMMA-ZrO2 hybrid coatings modified with HA and β-TCP to act as bioactive and corrosion protection coatings for Ti6Al4V alloys. In terms of cell growth and mineralization, osteoblast viability, Ca+2 deposition and alkaline phosphatase assays revealed a significant improvement for the HA and β-TCP modified coatings, compared to the bare alloy. This can be explained by an increase in nanoscale roughness and associated higher surface free energy, which lead to enhanced protein adsorption to promote osteoblast attachment and functions on the coatings. The effect of HA and β-TCP additives on the anticorrosive efficiency was studied by electrochemical impedance spectroscopy (EIS) in a simulated body fluid (SBF) solution. The coatings presented a low-frequency impedance modulus of up to 430GΩcm2, 5 decades higher than the bare Ti6Al4V alloy. These findings provide clear evidence of the beneficial role of HA and β-TCP modified hybrid coatings, improving both the biocompatibility and corrosion resistance of the Ti6Al4V alloy.

Ti6Al4V Alaşımına Sol-Jel Yöntemi ile Yapılan Hidroksiapatit Kaplamalarda Dietanolaminin Kaplama Morfolojisine ve Korozyon Dayanımına Etkisi

Titanyum ve alasimlari, mekanik dayanimlari ve biyotolerant yapida olmalari nedeni ile biyomalzeme uygulamalarinda tercih edilirler. Fakat insan vucudu icinde korozyona ugramasi durumunda zararli iyonlarin salinimina neden olabilirler. Hidroksiapatit ise seramik ve biyoaktif yapida bir malzeme olup biyomalzemelerin korozyon dayanimlarini arttirmaya yonelik kaplama tabakasi olarak kullanimi da mevcuttur. Bu calismada Ti6Al4V alasiminin korozyon dayanimini gelistirmek amaci ile sol-jel yontemi kullanilarak hidroksiapatit kaplamalar yapilmistir. Hazirlanan hidroksiapatit solusyonlarina farkli oranlarda dietanolamin (DEA, C4H11NO2) eklenerek sol-jel prosesinde olusmasi muhtemel olan catlakli yapilar kontrol edilmis ve azaltilmaya calisilmis ve kaplamanin genel morfolojisinde ve korozyon dayaniminda meydana gelen degisikliklerin gozlemlenmesi amaclanmistir. Numuneler taramali elektron mikroskobu (SEM-EDS) ve X-Isini kirinimi (XRD) kullanilarak analiz edilmistir. Hazirlanan yapay vucut sivisi icinde elektrokimyasal-potansiyodinamik korozyon testleri gerceklestirilmistir. Calismanin sonucunda DEA katki oraninin artmasi ile morfolojide catlakli yapilarin azaldigi ve kaplama kalinliginin arttigi gozlemlenmistir. DEA eklenmesinin korozyon dayanimini arttirdigi fakat DEA miktarindaki artisin korozyon dayanimini negatif etkiledigi gorulmustur.

Corrosion resistance of Ti6Al4V alloy by Radio Frequency Technique used for Coating Deposition of multilayer (HA/TiN/Ti6Al4V-substrate) for Optimization power

The objective of this study is to perform physical / chemical characterization and to determine the corrosion resistance of calcium-phosphate (HA), TiN-based bio-ceramics and thin metal plating processed by a Ti-6Al-4V process. TiN and HA coating maximum power 150 watts. The presence of TiN200 Watt TiN s coating resulted in electrochemical corrosion. High current cathodic and passive anodic polarization shows an active surface. EIS shows the active behavior assumed by the active cathodic currents imposed. And HA on the sample surface, some noise was observed during both polarization and EIS tests.

The Electrolytic Ionic Strength Effect on Corrosion Resistance and Crystallinity of Plasma Electrolytic Oxidation (PEO) Coating Developed on Ti6Al4V

The aim of this paper was to investigate the formation of an amorphous phase in the coating structure due to reduction in porosity and improvement in corrosion resistance of Ti6Al4V alloy during PEO process. The effect of crystallization on the electrochemical corrosion behavior and surface property of Ti6Al4V coating fabricated by plasma electrolytic oxidation (PEO) technique, was investigated in 5 wt %HCl solution. The coating compositions and electrochemical behaviors were examined by X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS) and polarization tests. The results showed that an increase in the ionic strength of electrolyte had a direct effect on the crystal size, the lattice strain and corrosion resistance. An increase in lattice strain due to Ti–O–Si led to a reduction in coating adhesion and corrosion resistance. A significant effect in phase transformation for Titania in the PEO process was not only led to an increase in polarization resistance but also reduced the number and size of porosity.

Corrosion Behavior of W-Mo Co-Penetrated Layer Produced by Glow Discharge Plasma Technique in Acid Solution

Abstract To improve the corrosion resistance of Ti6Al4V alloys in acid solution, a W-Mo co-penetrated top layer was prepared by hollow-cathode glow discharge plasma technique below the β phase transition point. The surface morphology, chemical composition and crystal structure of the coatings were determined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray power diffraction (XRD), respectively. Results indicate that a dense co-penetrated layer is produced with maximum thickness of approximately 23 μm. The layer is composed of AlMoTi2 and TixW1-x phases. The static corrosion test is conducted in acid (H2SO4 and HCl, separately) at room temperature (RT) by the electrochemical workstation. The results show that the W-Mo co-penetrated layer could achieve relatively stable corrosion potential in reducing acid and the Icorr of co-penetrated layers occupy merely 1/10 and 1/6 of that of Ti6Al4V substrates. In addition, there is barely any corroded product and crack on the corroded surface of co-penetrated layers, indicating no corroded shedding phenomenon occurs. So the corrosion resistance are obviously improved in the premise of keeping the basic properties of the substrate.

Corrosion Resistance of Ti6Al4V Alloy in Modified SBF Environments

The paper presents results of influence of modified artificial plasma on corrosion resistance of Ti6Al4V ELI alloy. The samples were subjected to grinding, anodic oxidation and steam sterilization. After 28-day exposure to Ringer’s solution as well as Tas - SBF and R - SBF fluids, studies of electrochemical impedance spectroscopy, corrosion resistance and the amount of metal ions released into the solutions were carried out. The obtained results were compared to the results obtained for the samples in the initial state. It was found that the highest reactivity in contact with the Ti6Al4V ELI alloy was observed for the Tas - SBF containing TRIS whereas the lowest reactivity was observed for the Ringer's solution. The obtained results indicate the possible use of the modified physiological solutions, in order to carry out a more rigorous test of corrosion resistance of metal materials.

Improving tribological and corrosion resistance of Ti6Al4V alloy by hybrid microarc oxidation/enameling treatments

A promising duplex coating was prepared by microarc oxidation (MAO) and enameling processes onto polished Ti6Al4V alloy. The TiO2 ceramic coating deposited by MAO was characterized and then combined with an enameling treatment in order to improve the tribological and corrosion resistance of Ti6Al4V alloy. The morphology, phase composition, and hardness of MAO and MAO/enameling-coated Ti6Al4V alloy were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Vickers microhardness tester, respectively. The tribological performance was investigated using a ball-on-disk tribometer. The corrosion resistance was studied using immersion tests and potentiodynamic polarization. Wear tests show that the enamel coating on the MAO-coated surface causes a reduction in the friction coefficient. Immersion tests demonstrate that the duplex coating is more effective in improving the corrosion resistance of Ti6Al4V than the MAO coating especially at high temperature (80 °C). Potentiodynamic polarization curves reveal that the corrosion potential of the duplex coating increases by about 250 mV and the corrosion current density is slightly lower than that of the MAO coating. The duplex coating is superior to the stand-alone MAO coating in improving the tribological and corrosion behavior of Ti6Al4V.

Dipcoating of poly (ε-caprolactone)/hydroxyapatite composite coating on Ti6Al4V for enhanced corrosion protection

Surface modification of metallic implants is often required to facilitate positive interaction between the implant and the surrounding hard tissue. In the present study, a polymer-ceramic composite coating of poly (ε-caprolactone)/hydroxyapatite (PCL/HA) was successfully deposited on a Ti6Al4V substrate by dip coating technique in chloroform suspension at room temperature. The influence of PCL concentration and dip coating parameters was studied and the process parameters were optimized to obtain a homogeneous, crack free, densely packed and adhesive coating. The surface of coating was rough and contained surface level pores, which are necessary for ingrowth of osseous tissue. The corrosion behaviour of the coated substrates was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), the results of which showed that the composite coating of PCL/HA substantially enhanced the corrosion resistance of Ti6Al4V alloy.